CN109959813B

CN109959813B - Multimeter capable of switching meter pens, host and control method thereof

Info

Publication number: CN109959813B
Application number: CN201910350694.4A
Authority: CN
Inventors: 段腾龙
Original assignee: Shenzhen Xingweifan Electronic Technology Co ltd
Current assignee: Shenzhen Xingweifan Electronic Technology Co ltd
Priority date: 2019-04-28
Filing date: 2019-04-28
Publication date: 2022-03-29
Anticipated expiration: 2039-04-28
Also published as: CN109959813A

Abstract

The invention discloses a multimeter capable of switching a meter pen, a host and a control method thereof. The universal meter comprises a meter pen and a universal meter host, wherein the meter pen is used for being connected with the universal meter host; the universal meter host is provided with two groups of sockets for inserting a meter pen, a meter pen motion block, a guide part and a first detection unit; the meter pen moving block can move along the guide part; the meter pen moving block is provided with two groups of moving contacts, and a plurality of groups of fixed contacts are arranged in the direction guided by the guide part; the two groups of moving contacts are respectively connected with the two groups of sockets; the two groups of moving contacts can be respectively contacted with the two different groups of fixed contacts; the first detection unit is used for enabling the movement contact to be conducted with the corresponding measurement circuit when the meter pen movement block reaches a specified position. The control method uses the multimeter host. The invention has simple operation, can reduce the times of inserting and pulling the meter pen and is convenient to use.

Description

Multimeter capable of switching meter pens, host and control method thereof

Technical Field

The invention relates to the technical field of measurement, in particular to a multimeter capable of switching a meter pen, a host and a control method thereof.

Background

Multimeters, also known as multiplex meters, multi-purpose meters, triple meters, multi-purpose meters, etc., are indispensable measurement instruments for power electronics and other departments, and generally aim to measure voltage, current and resistance. The multimeter is divided into a pointer multimeter and a digital multimeter according to the display mode, and is a multifunctional and multi-range measuring instrument. General multimeters can measure dc current, dc voltage, ac current, ac voltage, resistance, audio level, etc., and some can also measure ac current, capacitance, inductance, and some parameters of semiconductors.

The measurement of capacitance, inductance, resistance, alternating current and direct current voltage need not switch over the pen-shape metre, switches over through the inside simulation of universal meter or relay switch and just can reach the purpose of measurement. Because the internal resistance of universal meter current measurement gear is very little, for prevent that the user from appearing the mistake when using for example burning out the universal meter with current measurement gear measurement voltage, so with the probe socket separation of current measurement gear and voltage measurement gear, change the socket of probe when using current measurement gear. In order to enhance the conductivity, the stylus is in close contact with the socket, so that the stylus can be replaced only by using two hands during plugging and unplugging, which causes operation troubles, such as: in a measuring environment with poor lighting conditions, the meter pen is not easy to align to the socket.

Disclosure of Invention

In order to make up for at least one defect of the prior art, the invention provides a multimeter capable of switching a meter pen, a host and a control method thereof.

In order to solve the technical problems, the invention adopts the following technical scheme:

in a first aspect, the invention provides a multimeter host capable of switching a meter pen, wherein the multimeter host is provided with two groups of sockets for inserting the meter pen; the test pen also comprises a meter pen motion block, a guide part and a first detection unit; the meter pen moving block can move along the guide part;

the meter pen moving block is provided with two groups of moving contacts, and a plurality of groups of fixed contacts are arranged in the direction guided by the guide part, wherein each two groups of fixed contacts are connected with different measuring circuits;

the two groups of moving contacts are respectively connected with the two groups of sockets; the two groups of moving contacts can be respectively contacted with the two different groups of fixed contacts so as to be connected with different measuring circuits;

the first detection unit is used for enabling the movement contact to be conducted with the corresponding measurement circuit when the meter pen movement block reaches a specified position.

In some preferred embodiments, the first detection unit is further configured to: and when detecting that the function corresponding to the triggered key is different from the function corresponding to the specified position where the movement block of the meter pen is positioned, sending alarm information and/or disconnecting the path where the movement contact is positioned.

In some preferred embodiments, the fixed contact is a resilient conductive member, and the resilient conductive member is a resilient conductive sheet.

In some preferred embodiments, the first detection unit comprises a multimeter motherboard and a position detection circuit, and the multimeter motherboard is connected with the position detection circuit.

In some preferred embodiments, the position detection circuit is an infrared detection circuit, and a plurality of detection holes are further provided in the direction guided by the guide portion, and the infrared detection circuit can emit a signal through the detection holes to detect whether the stylus moving block is located at the designated position.

In some preferred embodiments, the stylus moving block is a stylus slider, and the guide portion is a slide.

In some preferred embodiments, each set of sockets includes a patch jack and a contact interface, the patch jack being connected to the moving contact.

In a second aspect, the invention provides a control method for a multimeter host capable of switching a meter pen, wherein the multimeter host is provided with two groups of sockets for inserting the meter pen; the meter pen moving block is provided with two groups of moving contacts which are respectively connected with the two groups of sockets;

the control method comprises the following steps:

and when the movement block of the meter pen is detected to be positioned at the designated position, the movement contact is conducted with the corresponding measurement circuit.

In some preferred embodiments, the method further comprises: and when detecting that the function corresponding to the triggered key is different from the function corresponding to the specified position where the movement block of the meter pen is located, disconnecting the path where the movement contact is located.

In a third aspect, the invention provides a multimeter with a switchable stylus, which comprises the stylus and the multimeter host, wherein the stylus is used for being connected with the multimeter host.

In a fourth aspect, the invention provides a method for controlling a multimeter, comprising the method for controlling the multimeter host; the universal meter comprises a meter pen and the universal meter host, wherein the meter pen is used for being connected with the universal meter host, and comprises a gear indicator and a measurement indicator;

the control method of the multimeter further comprises the following steps:

if the current measurement gear is the designated gear, controlling the gear indicator to output first information for indicating that the current measurement gear is the designated gear;

and controlling the measurement indicator to output measurement result information.

In some preferred embodiments, by the same channel:

sending a first communication signal to control the gear indicator to output the first information; sending a second communication signal to control the gear indicator to output second information for indicating that the current measured gear is a gear other than the specified gear; the first communication signal and the second communication signal comprise at least one first level signal and/or at least one second level signal; the voltage values of the first level signal and the second level signal are both within a first voltage value range; the first level signal lasts for a first length of time, and the second level signal lasts for a second length of time;

sending a third analog voltage signal with a voltage value within a third voltage value range to control the measurement indicator to output the measurement result information;

the first time length and the second time length are different time lengths; the third voltage value range is a different voltage value range than the first voltage value range.

In a fifth aspect, the invention provides a computer readable storage medium storing a computer program for use in conjunction with a computing device, the computer program being executable by a processor to implement the above-described method.

Compared with the prior art, the invention has the beneficial effects that:

when the current measuring gear of the universal meter needs to be used, the force is applied to the meter pen moving block to enable the meter pen moving block to move to the specified position corresponding to the current measuring gear along the guide part, the operation is simple, the number of times of inserting and pulling the meter pen can be reduced, and the use is convenient.

Drawings

FIG. 1 is a schematic diagram of a multimeter host of an embodiment of the present invention;

FIG. 2 illustrates the structure of a stylus body of an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a stylus body according to an embodiment of the present invention;

FIG. 4 illustrates the structure of a stylus plug according to an embodiment of the invention;

FIG. 5 is a first information interaction diagram of an embodiment of the present invention;

FIG. 6 is a second information interaction diagram according to an embodiment of the present invention;

FIG. 7 is a third information interaction diagram according to an embodiment of the present invention;

FIG. 8 illustrates the structure of a base of a multimeter host of an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a first control unit according to an embodiment of the present invention;

FIG. 10 shows a portion of the circuitry for the current measurement stage of an embodiment of the present invention;

FIG. 11 illustrates a portion of the control circuitry of a multimeter host of an embodiment of the present invention.

Detailed Description

Referring to fig. 1 to 11, embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application. The terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

First embodiment

Referring to fig. 1 to 4, the multimeter capable of switching pens of the embodiment comprises a multimeter host 1 and a pen 2, wherein the pen 2 can be connected with the multimeter host 1 so as to send signals to the multimeter host 1 or receive signals from the multimeter host 1.

Referring to FIG. 1, a multimeter host 1 is provided with two sets of sockets 10 for insertion of a stylus 2. The multimeter of this embodiment has two test pens 2 for insertion into two sets of sockets 10, respectively. Each set of sockets 10 comprises at least one port.

Referring to fig. 8 and 9, multimeter host 1 further includes a stylus movement block 11, a guide 12, and a first detection unit 13.

Referring to fig. 8, the stylus moving block 11 is movable along the guide portion 12. The form of the stylus moving block 11 includes a stylus slider and a stylus rotating block. Accordingly, the guide portion 12 is a slide for guiding the stylus slider or a circular groove for guiding the stylus rotation block. In the present embodiment, the stylus moving block 11 is a stylus slider, and the guide portion 12 is a slide.

Referring to fig. 8, the movement block 11 of the stylus pen is provided with two sets of movement contacts 111. Specifically, two sets of moving contacts 111 are respectively disposed on two sides of the movement block 11. When the stylus moving block 11 moves, the moving contact 111 follows the stylus moving block 11. Each set of moving contacts 111 includes at least one contact.

Referring to fig. 8, a plurality of sets of fixed contacts 121 are provided in the direction 120 in which the guide 12 is guided, wherein each two sets of fixed contacts 121 are connected to different measuring circuits. That is, every two sets of fixed contacts 121 are connected to one measurement circuit; if there are six sets of fixed contacts 121, there are three different measurement circuits. Each set of fixed contacts 121 includes at least one contact.

Specifically, referring to FIG. 8, guide 12 and fixed contacts 121 are disposed on base 13 of multimeter host 1.

The form of the measuring circuit specifically includes, but is not limited to, a direct current measuring circuit, a direct voltage measuring circuit, an alternating current measuring circuit, an alternating voltage measuring circuit, and a resistance measuring circuit.

Specifically, two sets of fixed contacts 121 are located on both sides of the guide portion 12, respectively.

The two sets of moving contacts 111 are respectively connected with the two sets of sockets 10. In the present embodiment, referring to fig. 8, two sets of sockets 10 are provided on the movement block 11, specifically, on both sides of the movement block 11. The sockets 10 are provided with conductive members, and the two sets of moving contacts 111 are connected with the conductive members of the two sets of sockets 10, respectively. In other embodiments, the ends of the conductive members of the two sets of sockets 10 act as two sets of moving contacts 111.

When the movement block 11 moves along the guide 12, the two sets of moving contacts 111 can contact with the two different sets of fixed contacts 121, so that the two sets of moving contacts 111 are connected with different measuring circuits.

Each two sets of fixed contacts 121 correspond to a designated position. When the movement block 11 moves along the guide 12 to a predetermined position, the two sets of moving contacts 111 are in contact with the corresponding two sets of fixed contacts 121, respectively.

The first detection unit 13 is used for making the moving contact 111 conduct with the corresponding measuring circuit when the stylus moving block 11 reaches the designated position.

In the present embodiment, referring to fig. 9, the first detection unit 13 includes a multimeter motherboard 131, a position detection circuit 132, and a first control unit 133. Multimeter motherboard 131 includes a plurality of measurement circuits, and first control Unit 133 is a Micro Control Unit (MCU). Multimeter motherboard 131 is connected to position detection circuitry 132 to acquire signals. In the present embodiment, the first detection unit 13 detects the position of the movement block 11 of the stylus pen by means of an infrared sensor, and accordingly, the position detection circuit 132 is an infrared detection circuit. A plurality of detection holes 122 are also provided in the direction 120 guided by the guide portion 12. Each detection hole 122 corresponds to two sets of fixed contacts 121, i.e., a designated position. Detection hole 122 is also provided on base 13 of multimeter host 1. Specifically, the guide portion 12 is two slide ways, and the detection hole 122 is located in the middle of the two slide ways.

In this embodiment, referring to fig. 8, the number of the detection holes 122 is three, and the detection holes are respectively a first detection hole, a second detection hole and a third detection hole, which are distributed from bottom to top in the drawing. Two test pens 2 are positioned in two groups of sockets 10 of the multimeter main body 1, and a test pen motion block 11 is positioned at a position corresponding to a first detection hole 122. At this time, the moving contact 111 is connected with an alternating current/direct current voltage, a resistor, a diode, a buzzer and a frequency measuring circuit inside the multimeter. When the measuring gear of the multimeter is changed from the previous measuring gear to the 3A current measuring gear, the pen-shape movement block 11 is forced to move along the guide part 12 to the position corresponding to the second detection hole 122. The two sets of moving contacts 111 are in contact with two sets of fixed contacts 121 corresponding to the 3A current measuring circuits, respectively. At this time, the stylus moving block 11 blocks the detection hole 122. The infrared signal that infrared detection circuit transmitted through inspection hole 122 is blocked, and infrared detection circuit produces a signal that indicates that pen-shape metre motion block 1 is located the assigned position and sends to universal meter mainboard 131. The multimeter motherboard 131 makes the moving contact 111 and the 3A current measurement circuit conducted, and specifically, the multimeter motherboard 131 may supply power to the 3A current measurement circuit or make a control switch inside the 3A current measurement circuit closed. Illustratively, referring to FIG. 10, the control switch is an analog switch, the fixed contact 121 is a 3A contact 121A, and the micro-control unit of multimeter motherboard 131 controls the analog switch using the sampled value of 3A sampling resistor 123. Thus, the current can be measured using the 3A current measurement tap.

The same is true when the current measuring gear position is changed to 10A, the movement block 11 of the meter pen is forced to move along the guide part 12 to the position corresponding to the third detection hole 122, referring to FIG. 10, the movement contact 111 is contacted with the 10A contact 121B, the micro control unit of the multimeter mainboard 131 controls the analog switch, and the 10A sampling resistor 124 is used for sampling the value. Thus, the current can be measured using the 10A current measurement tap.

According to the above, when the current measuring gear of the multimeter needs to be used, the force is applied to the meter pen moving block 11 to enable the meter pen moving block to move to the specified position corresponding to the current measuring gear along the guide part 12, the operation is simple, the number of times of inserting and pulling the meter pen can be reduced, and the use is convenient.

The multimeter only keeps two sets of sockets 10, the sockets 10 are fixed on the meter pen motion block 11, the meter pen 2 of the multimeter can be driven to be switched to a current measurement gear by sliding the meter pen motion block 11, the multimeter can be operated by one hand, and the switching is simple and quick.

The fixed contact 121 is an elastic conductive member. Specifically, the elastic conductive member is an elastic conductive sheet. When the moving contact 111 of the stylus moving block 11 contacts the fixed contact 121, the fixed contact 121 is deformed. After the moving contact 111 of the movement block 11 leaves the fixed contact 121, the fixed contact 121 is restored to its original state by its own elasticity. In this way, the movable contact 111 can be ensured to be reliably contacted with the fixed contact 121.

Referring to fig. 8, each set of jacks 10 includes a patch jack 101 and a contact interface 102. Patch jack 101 is connected to moving contact 111. The patch jack 101 is used to receive measurement signals from the stylus 2. The contact interface 102, which is used to send signals to the stylus 2, is provided with electrically conductive contacts. The socket 10 can supply power and required signals to the stylus 2, and it can be seen that the functions of the socket 10 are complex. Specifically, the contact interface 102 includes a power supply interface and an analog/digital signal output interface; in this manner, the multimeter host 1 can supply power to the stylus 2 or can send analog and/or digital signals to the stylus 2. The multimeter host 1 of the present embodiment can be used with a general purpose stylus, and can also be used with a multifunctional stylus that requires power supply and analog/digital signal provision. Of course, each set of jacks 10 may also include interfaces for outputting other communication signals.

The movement block 11 may be electrically driven, and when the key for switching the gear is triggered, the movement block 11 moves to a designated position.

The first detection unit 13 may also detect the position of the stylus moving block 11 by a switch such as a touch switch or a proximity switch. Wherein the proximity switch may be a hall switch.

Second embodiment

The first detection unit 13 is further configured to: and when detecting that the function corresponding to the triggered key is different from the function corresponding to the specified position where the movement block 11 of the stylus pen is positioned, opening the path where the movement contact 11 is positioned. The keys may be mechanical keys or virtual keys.

After the first detection unit 13 detects that the movement of the movement block 11 of the stylus pen reaches the designated position, the measurement function corresponding to the designated position is recorded, and the movement contact 11 is conducted with the corresponding measurement circuit. In this embodiment, the measurement function is to measure the current. During measurement, if the key for measuring voltage is triggered, the first detection unit 13 receives the signal and then determines that the function corresponding to the triggered key is not current measurement, that is, the triggered key is a non-current measurement key. At this time, the first detection unit 13 disconnects the path where the moving contact 11 is located, so that the multimeter is protected and prevented from being damaged.

Of course, the first detection unit 13 may send an alarm message to remind the user that the current operation is wrong, besides disconnecting the path where the moving contact 11 is located. The alarm information may be a sound, a light or a vibration.

Specifically, referring to fig. 11, the relay 134 has three pins, which are '1', '2', and '3', respectively. In a normal state, the signal of the relay control signal channel 100 is a low level signal, that is, the signal sent by the first control unit 133 to the relay 134 is a low level signal. At this time, pin '1' and pin '3' are conducted, so that the moving contact 11 is conducted with the corresponding measuring circuit on the multimeter motherboard 131. When the stylus moving block 11 is in the second detection hole or the third detection hole, if the non-current measurement key is triggered, the multimeter starts to alarm, and meanwhile, the signal of the relay control signal channel 100 changes into a high-level signal, the pin '1' and the pin '3' of the relay 134 are disconnected, so that the moving contact 11 is disconnected from the corresponding measurement circuit on the multimeter mainboard 131, and the access of the stylus 2 is cut off.

Third embodiment

Referring to fig. 2 to 4, the stylus 2 includes a stylus body 20, a stylus plug 24, and a lead 25. Referring to fig. 3, the stylus body 20 includes a gear indicator 21, a measurement indicator 22, and a second control unit 23.

The stylus plug 24 is connected to a wire 25. The meter pen 2 is connected with the multimeter host 1 through a meter pen plug 24. Specifically, a socket 10 is arranged on the multimeter host 1, and a stylus plug 24 is inserted into the socket 10 of the multimeter host 1.

The wire 25 is used for transmitting signals; specifically, the wire 25 is a multicore wire. The stylus 2 transmits signals to and receives signals from the multimeter host 1 via a conductor 25. Specifically, during measurement, an external signal is transmitted to the multimeter host 1 through the lead 25; the second control unit 23 receives signals transmitted by the multimeter host 1 via a conductor 25.

Referring to FIG. 2, a gear indicator 21 is used to indicate that the current measured gear of the multimeter is a designated gear; specifically, when the multimeter works, the current measurement gear of the multimeter is indicated to be a current measurement gear, a voltage measurement gear or a resistance measurement gear; that is, the designated gear may be a current measurement gear, a voltage measurement gear, or a resistance measurement gear, and is specifically set as required.

Referring to FIG. 2, a measurement indicator 22 is used to indicate measurement information of the multimeter; specifically, when the multimeter is in operation, the current, voltage or resistance, etc. currently measured is indicated, or information related to the current, voltage or resistance currently measured is indicated. The measurement result information may also be information that the measurement value is out of range, such as that the measurement voltage is out of range.

The second control Unit 23 may be a Micro Control Unit (MCU).

The control method of the present embodiment will be described, including a control method of a multimeter and a control method of a stylus of the multimeter.

In the case of a multimeter, voltage is measured at a current measurement gear, which can easily cause damage to the multimeter. In order to remind the user, in the present embodiment, the designated gear is a current measurement gear.

If the current measurement gear is the current measurement gear, the control gear indicator 21 outputs first information indicating that the current measurement gear is the current measurement gear. Specifically, the multimeter host 1 sends a signal indicating that the current measurement gear is the current measurement gear to the second control unit 23, and after the second control unit 23 receives the signal, the second control unit controls the gear indicator 21 to output the first information. Wherein, the first information is yellow light, that is, the gear indicator 21 emits yellow light; in some embodiments, the first information is vibration or speech; therefore, the user can be reminded of paying attention to the fact that the current measuring gear is the current measuring gear. In this case, the shift indicator 21 is a light emitting device. Of course, the current measuring gear corresponds to yellow light, and other gears may correspond to white light or other colors of light.

In the measuring process, the multimeter host 1 converts the voltage value of the received external measuring signal according to a set proportion, ensures that the voltage value range conforms to the set voltage value range, and obtains a signal which indicates the number of the measured value after conversion; specifically, the multimeter host 1 divides an external signal with a relatively high voltage or amplifies a signal with a low voltage, so that a measured analog signal is always within a set voltage value range, specifically, always within a range of more than or equal to 0V and less than or equal to 2.5V. Multimeter host 1 sends the converted signal to control unit 23. The control unit 23 reads and processes the converted signal, and the second control unit 23 controls the measurement indicator 22 to output measurement result information after receiving the signal. Specifically, the measurement result information is a measurement value or information related to the measurement value. The information related to the measurement value may be a percentage of the span, may be a percentage of the voltage span or a percentage of the current span. The measurement result information may be in the form of a light, and specifically, the measurement value or a position corresponding to the information related to the measurement value emits light.

Take the measured voltage as an example. In the process of measuring voltage, the externally supplied voltage is 10V, the multimeter host 1 automatically switches the measurement channel (the range is 20V) according to the received voltage signal to perform 1/10 voltage division, the measurement signal at this time becomes 1V, and the signal is output to the signal contact 242. The second control unit 23, upon receiving the signal, controls the measurement indicator 22 to output measurement result information. The position on the gauge indicator 22 corresponding to (1/2) × 100% emits light, assuming there are 10 light emitting devices, corresponding to 0V to 20V, respectively. As such, the 5 th light emitting device may emit light, or the 1 st to 5 th light emitting devices may all emit light; or the position corresponding to 50% emits light, and assuming that there are 10 light emitting devices, corresponding to 0% to 100%, respectively, so that the 5 th light emitting device emits light, or the 1 st to 5 th light emitting devices all emit light. The light emitting device may be an LED lamp.

According to the above, if the current measurement gear is the current measurement gear, the gear indicator 21 of the meter pen 2 outputs the first information indicating that the current measurement gear is the current measurement gear, so as to remind the user of the current measurement gear, thereby preventing the user from using the current measurement gear to measure the voltage. During the measurement, the measurement indicator 22 of the stylus 2 outputs measurement result information so that the user can see the measurement result directly on the stylus 2. Therefore, the embodiment is convenient to use and can improve user experience.

Fourth embodiment

The gear indicator 21 indicates the state, which is realized by the received digital signal. And the measurement indicator 22 indicates a value, which is realized by means of a received analog signal. It is common practice to use one channel to transmit digital signals and another channel to transmit analog signals. The use of two channels not only requires two corresponding circuits to generate the digital and analog signals, but also requires two lines as channels, which complicates the construction of the multimeter and increases the cost.

In the control method of the fourth embodiment, the digital signal and the analog signal are transmitted through one channel, that is, the digital signal and the analog signal are transmitted through the same channel.

The following description is directed to indicating the current measurement range of the multimeter.

Referring to FIG. 5, multimeter host 1 sends a first communication signal to control unit 23. In this embodiment, the first communication signal includes a first level signal and a second level signal, the first level signal is before and the second level signal is after. In order to facilitate the identification of two level signals, for the first communication signal, the interval between the first level signal and the second level signal is a first interval time; specifically, the first interval time is greater than 10us and less than 20 ms. After receiving the first communication signal, the control unit 23 recognizes that the first communication signal includes two level signals, i.e. two bits (bit) corresponding to the digital signal, wherein the first is the first level signal, and the second is the second level signal. The control unit 23 determines the voltage value range and the duration length of the level signal, thereby identifying whether the level signal is the first level signal or the second level signal. If the voltage value of the level signal is within the first voltage value range and lasts for the first time length, the level signal is the first level signal. And if the voltage value of the level signal is within the first voltage value range and lasts for a second time length, the level signal is a second level signal. The first voltage value range, the first time length and the second time length can be set according to specific needs, wherein the second time length is different from the first time length. Illustratively, the first voltage value range is 3V to 5.0V, the first time length is 25ms ± 2ms, and the second time length is 15ms ± 2 ms. In this embodiment, 3V to 5.0V are communication levels, the first level signal is a high level signal, and the second level signal is a low level signal. According to a predetermined protocol, the control unit 23 recognizes that the first communication signal is a two-bit communication signal, which is "0B 10"; "0B" represents a binary system, "1" represents a first level signal, i.e., a high level signal, and "0" represents a second level signal, i.e., a low level signal. "0B 10" represents that the current measured gear position is the specified gear position, and the control unit 23 controls the gear position indicator 21 to output the first information so that the gear position indicator 21 indicates that the current measured gear position is the specified gear position.

Referring to FIG. 6, multimeter host 1 sends a second communication signal to control unit 23. In this embodiment, the second communication signal includes two second level signals, one behind the other. The interval between the two second level signals is the first interval time. After receiving the second communication signal, the control unit 23 recognizes that the second communication signal includes two level signals, specifically, two second level signals, that is, two low level signals. According to the predetermined protocol, the control unit 23 recognizes that the second communication signal is a two-bit communication signal, which is "0B 00"; "0B" represents a binary system, and "0" represents that both level signals are the second level signal, i.e., a low level signal. "0B 00" represents that the current measured gear position is a gear position other than the specified gear position, and the control unit 23 controls the gear position indicator 21 to output second information indicating that the current measured gear position is a gear position other than the specified gear position. The gear other than the designated gear may be a resistance gear, a voltage gear, or other gears. The second information may be in the form of white lights, vibrations, speech or other forms. The second information is different from the first information in specific content so as to remind a user whether the current measured gear is a designated gear or a gear other than the designated gear.

The voltage values of the first level signal and the second level signal are both in the first voltage value range, but the duration of the first level signal is different from that of the second level signal. The length of time during which the first level signal and the second level signal last may be controlled by a timer.

The following is a description of the measurement results indicating a multimeter.

Referring to FIG. 7, in performing a measurement, multimeter host 1 sends a third analog voltage signal having a voltage value within a third voltage value range to second control unit 23; the third voltage value range is the set voltage value range, and is greater than or equal to 0V and less than or equal to 2.5V. After receiving the analog voltage signal, the second control unit 23 determines whether the analog voltage signal is a third analog voltage signal, specifically, determines whether the voltage value of the analog voltage signal is within a third voltage value range. If so, the measurement indicator 22 is controlled to output measurement result information.

Since the third voltage value range is different from the first voltage value range, it is already possible to distinguish the third analog voltage signal from the first level signal and the second level signal. A certain vacant range exists between the first voltage value range and the third voltage value range; specifically, as can be seen from the foregoing, the third voltage range is 0V to 2.5V, the first voltage range is 3V to 5V, and a spare range (2.5V,3V) exists between the third voltage range and the first voltage range, so as to avoid misjudgment of the communication signal.

In the measuring process, when a measuring gear is switched, the multimeter host 1 sends a first communication signal or a second communication signal to the meter pen 2, and if the measuring gear is not switched, a third analog voltage signal is sent all the time to indicate a measuring result.

In other embodiments: the first communication signal comprises a first level signal, the content of the first communication signal is '0B 1', and the first communication signal represents that the current measurement gear is the designated gear; the second communication signal includes a second level signal, and the content of the second communication signal is "0B 0", which represents that the current measured gear is a gear other than the designated gear. Of course, the number of the level signals included in the first communication signal and the second communication signal may be three or more.

As can be seen from the above, the first level signal and the second level signal are communication levels; the voltage values of the first level signal and the second level signal are both in a first voltage value range; but the duration of the first level signal and the second level signal are different; thus, the first level signal and the second level signal can be distinguished. The third analog voltage signal is an analog signal indicative of a measurement of the multimeter. The range of voltage values of the third analog voltage signal is different from the first level signal and the second level signal. Thus, when the first level signal, the second level signal and the third analog voltage signal are transmitted through the same channel, the first level signal, the second level signal and the third analog voltage signal can be distinguished. The voltage signals may be generated as the first level signal, the second level signal and the third analog voltage signal by a circuit which only has to distinguish between two voltage ranges, also for the second control unit 23.

In general, the high and low levels are two voltage ranges, and the voltage range of the added analog voltage signal is three voltage ranges. Then each voltage range is relatively narrow. When the voltage signal is affected by external influences, such as electromagnetic interference, during transmission, the voltage value of the voltage signal is reduced, which may result in that the high level is mistakenly judged as the low level. In this embodiment, the voltage ranges of the voltage signals are two, and each voltage range can be set to be wider, so that the anti-interference capability of the signals is improved. This embodiment can realize transmitting digital signal and analog signal through the single channel, can simplify the structure of universal meter, can improve the interference killing feature of signal.

In some embodiments, the third range of voltage values includes a normal range and an over-range, and if the voltage of the third analog voltage signal is within the over-range, the measurement indicator 22 outputs information indicating that the measurement value is beyond the current range, specifically, the corresponding light emitting device on the measurement indicator 22 emits light. As described above, the third voltage value range is 0V to 2.5V, wherein greater than or equal to 0V and less than 2V is the normal range, and greater than or equal to 2V and less than or equal to 2.5V is the over range.

Fifth embodiment

Referring to fig. 4, the stylus plug 24 includes a plug post 241, a signal contact 242, a first power contact 243, and a second power contact 244, which are connected to different wires of the wire 25, respectively. Thus, wire 25 is a four-core wire, i.e., having four cores.

Referring to fig. 2, stylus body 20 also includes a stylus probe 26.

The plug terminal 241 is connected to the stylus probe 26 via a core of the line 25. When plug terminal 241 is connected to multimeter host 1, stylus probe 26 can transmit measurement signals or external signals to multimeter host 1.

The signal contact 242 is connected to the stylus main body 20, in particular to the second control unit 23 of the stylus 2, by one core of the wire 25. When signal contact 242 is connected to multimeter host 1, second control unit 23 can receive signals transmitted by multimeter host 1.

After the first power contact 243 and the second power contact 244 are connected with the multimeter host 1, power is supplied to the meter pen 2, specifically to the gear indicator 21, the measurement indicator 22 and the second control unit 23, through one core wire of the lead 25. The first power supply contact 243 and the second power supply contact 244 are specifically a 5V contact and a GND contact, respectively. So for the pen-shape metre 2 has the illumination function of external power supply, can avoid adorning the battery on the pen-shape metre for the power supply of the LED light on the pen-shape metre 2, and then can avoid the life of battery and the inconvenience that brings when the relatively thick and big pen-shape metre uses.

It can be seen that the stylus plug 24 carries both a power supply interface and a communications interface.

Referring to fig. 2, the gear indicator 21 specifically includes an indicator light (not shown) and a light guide 211 provided at one end of the stylus main body 20. The indicator light is a double-color LED light. The light guide 211 is specifically an illumination light guide column. The indicator light is yellow when the current measuring gear is used and white when the current measuring gear is not used. In this way, the user can also use the gear indicator 21 on the stylus 2 for illumination during the measurement.

Referring to fig. 2, the measurement indicator 22 specifically includes a number indicator 221, a light-emitting unit (not shown in the figure), and a plurality of indicators 222. The numerical indicator 221 is provided on the case 27 of the stylus body 20. The indication portion 222 is an indication hole provided in the housing 27. The light emitting unit is located inside the housing 27. The light emitted from the light emitting unit may pass through the indication portion 222, thereby performing an indication function. Indicator 222 may also be a light guide strip that is wrapped around housing 27, specifically an annular light guide strip wrapped around housing 27.

The measurement indicator 22 may indicate the measurement value using a digital tube, an LCD, a liquid crystal display, or the like, in addition to the measurement value by using an LED lamp.

The gauge indicator 22 is not limited to being controlled by the second control unit 23, in other embodiments the gauge indicator 22 is driven by a resistive divider or other analog circuit.

Sixth embodiment

The present embodiments provide a computer-readable storage medium storing a computer program for use in conjunction with a computing device, the computer program being executable by a processor to implement the above-described method.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention.

Claims

1. The utility model provides a control method of changeable pen-shape metre universal meter, the universal meter includes pen-shape metre and universal meter host computer, the pen-shape metre be used for with the universal meter host computer is connected, the pen-shape metre includes gear indicator and measurement indicator, its characterized in that: the universal meter host is provided with two groups of meter pen sockets for inserting meter pens; the test pen also comprises a meter pen motion block, a guide part and a first detection unit; the meter pen socket is fixed on the meter pen moving block, and the meter pen moving block can move along the guide part;

the two groups of moving contacts are respectively connected with the two groups of meter pen sockets; when the meter pen moving block slides along the guide part, the two groups of moving contacts can be respectively contacted with the two different groups of fixed contacts so as to be connected with different measuring circuits; the fixed contact is an elastic conducting strip, when the movement contact is contacted with the fixed contact by the movement block of the meter pen, the fixed contact is deformed, and after the movement block of the meter pen slides to the movement contact and leaves the fixed contact, the fixed contact is restored to the original state under the action of the elasticity of the fixed contact, so that the connection with different measuring circuits can be switched by sliding the movement block of the meter pen;

the first detection unit is used for enabling the movement contact to be conducted with the corresponding measurement circuit when the meter pen movement block reaches a specified position;

the control method of the multimeter comprises the following steps:

when the movement block of the meter pen is detected to be positioned at the designated position, the movement contact is conducted with the corresponding measurement circuit; when detecting that the function corresponding to the triggered key is different from the function corresponding to the specified position where the movement block of the meter pen is located, disconnecting the path where the movement contact is located;

controlling the measurement indicator to output measurement result information;

through the same channels:

2. The control method according to claim 1, characterized in that the first detection unit is further configured to: and when detecting that the function corresponding to the triggered key is different from the function corresponding to the specified position where the movement block of the meter pen is positioned, sending alarm information and/or disconnecting the path where the movement contact is positioned.

3. The control method according to claim 1, characterized in that: the first detection unit comprises a universal meter mainboard and a position detection circuit, and the universal meter mainboard is connected with the position detection circuit; the position detection circuit is an infrared detection circuit, a plurality of detection holes are further formed in the guiding direction of the guide portion, and the infrared detection circuit can transmit signals through the detection holes to detect whether the movement block of the meter pen is located at the designated position.

4. The control method according to any one of claims 1 to 3, characterized in that: each group of the jacks comprises a wiring jack and a contact interface, and the wiring jack is connected with the moving contact; the meter pen motion block is a meter pen sliding block, and the guide part is a slide way.

5. A computer-readable storage medium storing a computer program for use in conjunction with a computing device, the computer program being executable by a processor to implement the method of claim 1 or 2.